BOBBY JINDAL

GOVERNOR

PEGGY M. HATCH

SECRETARY

~tate of JLouisiana

DEPARTMENT OF ENVIRONMENTAL QUALITY

ENVIRONMENTAL SERVICES

Mr. Thomas H. Diggs

Associate Director, Air Programs (6PD)

U.S. Environmental Protection Agency, Region 6

1445 Ross Avenue, Suite 1200

Dallas, TX 75202-2733

Dear Mr. Diggs:

This letter serves to clarify the Louisiana Department of Environmental Quality's (LDEQ's)

position regarding the use ofPMlO as a surrogate for PMZ.5.

EPA's final rule entitled "Implementation of the New Source Review (NSR) Program for

Particulate Matter Less Than 2.5 Micrometers (PMZ.5)," was promulgated on May 16,2008. 1 In

this rule, EPA acknowledges that:

States with SIP-approved PSD [Prevention of Significant Deterioration] programs

that require amendments to incorporate these final NSR rule changes for PMZ.5

will need time to accomplish these SIP amendments. For example, a State may

need to amend its existing regulations to add the specific significant emissions

rate for PM2.5 or a designated precursor.Z

Accordingly, the rule specifies that states with SIP-approved PSD programs, like Louisiana,

must submit revised PSD and Nonattainment New Source Review (NNSR) programs for PMZ.5

by May 16, 2011.3 EPA further elaborates on applicable requirements during the "transition"

period, then concludes with why the agency believes this approach is reasonable.

During this SIP development period, the PMz.5 NAAQS must still be protected

under the PSD program in such States. We are finalizing our proposed option 1

that if a SIP-approved State is unable to implement a PSD program for the PMz.5

NAAQS based on these final rules, the State may continue to implement a PMlO

program as a surrogate to meet the PSD program requirements for PMZ.5pursuant

to the 1997 guidance mentioned previously [i.e., the PMlO Surrogate Policy].4

We believe that our final rule is reasonable for the following reasons. First, PMlO

will act as an adequate surrogate for PMZ.5 in most respects, because all new

major sources and major modifications that would trigger PSD requirements for

PMz.5 would also trigger PMlO requirements because PMZ.5 is a subset of PMlO.

Second, both of the precursors designated in the final rule - SOz and NOx

(presumptively) - are already regulated under State NSR programs for other

criteria pollutants. Thus, those precursors will be subject to NSR through those

other programs.5

1 73 FR28321

2 73 FR28340

3 73 FR28341

4 Ibid.

5 Ibid.

Post Office Box 4313 • Baton Rouge, Louisiana 70821-4313 • Phone 225-219-3181 • Fax 225-219-3309

www.deq.louisiana.gov
Mr. Thomas H. Diggs

Page 2

On February 11, 2010, EPA proposed to end early the PMlO Surrogate Policy applicable to SIPapproved states; however, this proposal has not been finalized to date. 6

Louisiana has not yet adopted the provisions ofEPA's PM2.5 NSR Implementation Rule, but will

propose a rule to do so in early 2011.

In the interim, in light of "In the Matter of: Louisville Gas and Electric Company" (Petition IV2008-3) and EPA's directive that permitting authorities must "demonstrate that PMlO is a reasonable

surrogate for PM2.5," LDEQ is generally requiring all applicants proposing significant increases in

PM2.5 emissions which would be subject to PSD review under the federal program to conduct both

BACT and air quality impact analyses. However, should LDEQ choose to rely on EPA's PMlO

Surrogate Policy, LDEQ will not proceed on the general presumption that PM10 is always a

reasonable surrogate for PM2.5 and will include in the permit record an adequate rationale or

demonstration to support the use of PMlO as a surrogate based on the facts and circumstances of

the specific perinit action.

Should you have any questions concerning this matter, please feel free to contact Bryan D.

Johnston ofthe Air Permits Division at (225) 219-3450.

Sincerely,

UUc--

Cheryl Sonnier Nolan

Assistant Secretary

CSN:BDJ

6 75 FR 6827

Ja~~/O Date